Controlliitg proportions



- w. E. HARVEY. CONTROLLING PROPORTIONS 0F PULVERIZED FUEL MIXTURE.

' APPLICATION FILED MAR. 7, 1919. Patented Aug. 3, 1920.

2 SHEETS-SHEET 1.

W. E. HARVEY; CONTROLLING PROPORTIONS 0F PULVERIZED FUEL MIXTURE.

APPLI-CATION FILED MAR-7,1919. 1,348,561.

Patented Aug. 3, 1920.

2 SHEETS-SHEET 2.

nabv WITIMRSFS-ES INVENTOR UNITED STA S PATENT OFFICE.

WILBER IE. HARVEY, 0F GL ENSHAW, PENNSYLVANIA.

CONTROLLING PROPORTIONS 8F PULVERIZED-FUEL MIX'IURE.

Application filed March 7,

To all whom it may concern:

Be it known that I, VVILBER E. HARVEY, residing at Glenshaw,"in thecounty of Allegheny and State of Pennsylvania, a citizen of the UnitedStates, have invented or discovered certain new and useful Improvementsin Controlling Proportions of ,Pulverized-Fuel lWiXture, of whichimproyement the following is a specification.

My invention has to do with the art of burning solid fuel which. in afinely divided or pulverized state, is carried in suspension in aflowing stream ofcombustiohsupporting gas. While applicable to theburning of different kinds of pulverized combustible fuelmy inventionfinds particular adaptability to the burning of" coal dust suspended inair, and it is with reference to such particularuse that I will describeit.

In using, as a fuel for burners in a manufacturingplant, coal dustsuspended in a stream of air, the usual practice is to reduce the coalto a pulverized condition at a crushing station at or near theplant,'and to mix the pulverized coal with a continuously flowingstreamlof air under pressure. A main conduit for carrying the mixture ofair and coal dust is extended to the parts of the plant at which it isdesired to burn the fuel, and for. each burner or set, of burners aportion of the mixture is abstracted from the? main conduit andconducted to the burner by means of a branch conduit. The initialmixture is usually formed with an excess ofcoal dust, that is to say,the mixture does not contain sulficient air to effect completecombustion of the coal, andaccordingly additionalair is supplied to eachburner by means of a' suitable blast.

For abstracting, for a burner, a pertion of the. mixture from the mainconduit, the inlet end of the branch conduit is usually provided with avalve." It will be understood that such valve merely controls the amountofa givenmixture'thatis permitted to flow through the branch conduit,or, in otherwords, that the valve does not have the efi'ect of varyingthe relative proportions of the mixture fed to a burner. Considerabledifiiculty has been experienced in the use of such controlling valves inbranch conduits by reason of the fact that they so obstruct the passageofthe branch conduit that coal dust deposits in thebranch conduit and isfrequently ejected in mass,

Specification of Letters Patent.

Patented Aug. 3 1920. 1919. Serial No. 281,287.

causing undesirable puffs in the flame, and, occasionally disastrousexplosions.

The object of my invention is to provide means whereby variable relativeproportions of a mixture of a combustionsupporting gas and combustibleparticles may be abstracted from a main conduit and fed to a burnerthrough a branch conduit having an unobstructed passageway.

In the accompanying sheets of drawings, which form part of myspecification, I have illustrated the preferred embodiment of myinvention/ Figure l is an elevation of a plurality of -furnaces, a mainconduit, and branch conduits extending from the main conduit to thefurnaces; Fig.2 a vertical sectional view taken on the line .lI-H, Fig.1; Fig. 3 an enlarged view of a portion of the main conduit and theupper por tion of a branch conduit; Fig. 4 a sectional view taken on.the line lV-IV, Fig. 3;.

and Fig. 5 a sectional view taken on the line VV, Fig. 4:.

Referring to the drawings, the main conduit ,1 tor carrying the mixtureof coal dust and air is indicated as extending above a plurality offurnaces 2 which may be of any suitable construction and for any desiredpurpose, as for example, the heating of steel or other metals. As isusual in in stallations for burning coal dust, the main two burners 3,which also may be of any suitable type or construction, Extending."fromthe main conduit 1 to each burner 3 there is an unobstructedconduit 4.

At the inlet end of each branch conduit I provide means whereby variableamounts of coal dust may be abstracted from the main conduit withoutsubstantially varying the amount of air so abstracted, or inother words,means whereby variable relative quantities of coaldust and air may be soabstracted. While various means may be usedto such end, Ipreferablyprovide a funnel-like orifice m ember 5 having aninletvopening 14., preferably of unvarying size, which member may be so"turned, or otherwise adjusted that the general plane ofits inletopening may lie at various angles to the line of flow through the mainconduit. v

Any suitable means may be provided for turning the orifice member 5.lnthe illustrative embodiment of my invention a pinion 6 is keyed toth'emember 5, and, meshmg wlth such p1n1on, there is a second pmion 11keyed to a rod 12 extending downwardly to within easy reach of a workmanin. front ofa furnace 2. The orifice memher is rotatably mounted ina-saddle 15 secured to the main conduit 1 by yolres 16.

.The lower end of the saddle is provided with a flange 17 to which thereis attached, as by means of bolts 18, a flange 190i a valve casing 20, asuitable spacer 8 being interposedbetweenthe flanges 17 and 19 got such"thickness as to permit rotation of .stract'themaximum amount orproportion of coal dust,.the member 5 is turned to the positionindicated in the drawing, the orifice l4 fully facing the line of flow,indicated by .the arrow 22, through the main conduit.

hen it is desired to diminish the amount ofcoal dust abstracted,.theorifice member is turned'eitlierto the right or to the left an amountdepending upon the diminished supply. desired. It will be. understoodthat, when the orifice is set at an angle to the line of flow, a lessproportion of coal dust will be received than when the orifice fullyfaces the line of flow, assuming, of course,

i that at the point of abstraction the relative mixture ofcoal .du st and airjiremains the same. .Generally speaking, the ratio betweenthelalnount of coal dust abstracted by the orifice when fully facingtheline of flow and when placed; at an angle to such line of flow issubstantially the same as the ratiobetween the projections of theorifice on planes at right angles to the line of flow.

Because of the pressure under which the air flows, that 1s-to say thestatic pressure as distinguished- :trom thevelocity pressure, the

amount of air abstracted by the orificewill, within the practicalrangeof adjustment of the orifice be substantially the same when theorifice is placed at an angle to, as when fully facing the l-ineoi flow;Accordingly,

by adjusting the position of the orifice, the relative quantities of airand coal dust abstracted may be varied to meet requirements,

and at the same time a strong flow oi the mixture through eachunobstructed branch conduit may be maintamed.

For two reasons the relative quantities of coal dust and air carried bythe, main coni duit varies with the distance of the main conduit-fromthe point of initial mixture. In thefirst place a certain amount of thecoal dust gradually settles to, and toa large extentrema-insupon, thebottom of the conduit. Such dust is periodically blown or otherwiseremo'vedgfrom theqmain conduit.

Secondly, the withdrawal of portions of the mixture through the branchconduit varies the relative proportion of air and coal dust, theproportion of coal dust usually being diminished. By providing meanssuch as shown herein, or its equivalent, for varying the relativequantities of coal dust and air abstracted from the main conduit, thecharacter of the flame supported by the mixture taken from any pointalong the mam conduit may, independently of a supplemental blast, becontrolled according to requirements. In other words by varying therelative quantities of coal dust and air abstracted, either a smokycarbonizing, or a white oxidizing flame may be had regardless of thevariation of the mixture in the main conduit.

According to the provisions of the patent statutes, I have described theprinciple and operation of my invention together with the apparatuswhich I now consider to represent the best embodiment thereof. However,-I desire to have it understood that. within the scope of the appendedclaims. my

invention may be practised by other forms of apparatus than that shownand, descriluad.

I claim as my invention:

1. The combination with a main conduit for carrying a flowing stream oicombustion-supporting gas having solid combustible particles suspendedtherein, a burner. and a branch conduit extending from said main conduitto said burner, of an orifice member for abstracting from the mainconduit a portion of said stream oi and particles and delivering saidportion to said branch conduit. and means For rendering said orificemember effective to vary the relative quantities or said gas andparticles abstracted. from the main conduit through the branch conduit.

2. The combination oi a main conduit for carrying the flowing stream ofcombustionsupporting gas having solid particles suspended therein. aburner, a; branch conduit extending rom said main conduit to saidburner, and means at the inlet end of said branch conduit forabstracting from the main conduit variable relative quantities of saidgas and particles.

3. The combination with a main conduit for carrying a flowing stream ocombustion-supporting gas having solid particles suspended therein, aburner. and a branch conduit extending from said main conduit to saidburnerof an orifice member in said main conduit and communicating withsaid branch conduit, and means for adiusting the general plane of theorifice of? said member with respect to the longitudinal axis of saidmain conduit wherebv variable relative fluantities of said gas andparticles may be 4. The combination of a main conduit for carrying aflowing stream of combustionsupporting gas having solid particlessuspended therein, a burner, an unobstructed branch conduit extendingfrom said main conduit to said burner, and means at the inlet end ofsaid branch conduit for abstracting from the main conduit variablerelative proportions 01. said gas and particles.

5. The combination with a main conduit for carrying a flowing stream ofcombustion supporting gas having solid particles suspended therein, aburner, and a branch conduit extending from said main conduit to 15 withrespect to the longitudinal axis of said 20 main conduit.

In testimony whereof I have hereunto set my hand.

WILBER E. HARVEY.

Witnesses:

Amen A. TRILL, PAUL N. CRrroHLow.

